"The sacrifice of fools"in view (v. 1) is a rash vow, as is clear from what follows. Verse 3 seems to compare the verbosity of a fool in making a rash vow to God and the endless dreams one often experiences after a very busy day. Much work generates many dreams, and a fool utters too many words.47If a person makes a rash promise to God and then does not keep it, God may destroy the work of his hands (v. 6). Pleading with the priest ("the messenger of God,"v. 6) that the vow was a mistake would not excuse the vow-maker (cf. Deut. 23:21-23).
"Our promise may involve giving to some special work of God or pledging prayer and other support for a missionary. When the representative of the work looks for the fulfillment of our promise, we must not draw back and make an excuse about not having understood what we were required to do."48
Verse 7 uses dreams to illustrate emptiness. "Fear God"(v. 7) also occurs in 3:14; 7:18; 8:12, 13; and 12:13.
". . . we should try to put ourselves in a position to discover God's way to use what he has given us in our daily life."49
(NT only) to listen to the NET Bible 
